Performance improvements

core/src/main/java/de/congrace/exp4j/ExpressionBuilder.java

@@ -48,7 +48,7 @@ public class ExpressionBuilder {
 			for (String name : variables.getVariableNames()) {
 				function.append(name).append(',');
 			}
-			expression = function.deleteCharAt(function.length() - 1).toString() + ")=" + expression;
+			expression = function.deleteCharAt(function.length() - 1) + ")=" + expression;
 		}
 		// create the PostfixExpression and return it as a Calculable
 		PostfixExpression delegate = PostfixExpression.fromInfix(expression, customFunctions);

core/src/main/java/de/congrace/exp4j/Tokenizer.java

@@ -218,6 +218,6 @@ class Tokenizer {
 			}
 			tokens.add(lastToken);
 		}
-		return tokens.toArray(new Token[tokens.size()]);
+		return tokens.toArray(new Token[0]);
 	}
 }

core/src/main/java/info/openrocket/core/aerodynamics/BarrowmanCalculator.java

@@ -534,9 +534,9 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
 		
 		// Correct body data in map
 		if (forceMap != null) {
-			for (RocketComponent c : forceMap.keySet()) {
+			for (Map.Entry<RocketComponent, AerodynamicForces> entry : forceMap.entrySet()) {
-				if (c instanceof SymmetricComponent) {
+				if (entry.getKey() instanceof SymmetricComponent) {
-					forceMap.get(c).setFrictionCD(forceMap.get(c).getFrictionCD() * correction);
+					entry.getValue().setFrictionCD(entry.getValue().getFrictionCD() * correction);
 				}
 			}
 		}

core/src/main/java/info/openrocket/core/file/motor/AbstractMotorLoader.java

@@ -134,7 +134,7 @@ public abstract class AbstractMotorLoader implements MotorLoader {
 	 */
 	protected static String[] split(String str, String delim) {
 		String[] pieces = str.split(delim);
-		if (pieces.length == 0 || !pieces[0].equals(""))
+		if (pieces.length == 0 || !pieces[0].isEmpty())
 			return pieces;
 		return ArrayUtils.copyOfRange(pieces, 1, pieces.length);
 	}

core/src/main/java/info/openrocket/core/file/openrocket/importt/ColorSetter.java

@@ -47,7 +47,7 @@ class ColorSetter implements Setter {
 		ORColor color = new ORColor(r, g, b);
 		setMethod.invoke(c, color);
 		
-		if (!s.trim().equals("")) {
+		if (!s.trim().isEmpty()) {
 			warnings.add(Warning.FILE_INVALID_PARAMETER);
 		}
 	}

core/src/main/java/info/openrocket/core/file/openrocket/importt/MaterialSetter.java

@@ -28,7 +28,7 @@ class MaterialSetter implements Setter {
 
 		// Check name != ""
 		name = name.trim();
-		if (name.equals("")) {
+		if (name.isEmpty()) {
 			warnings.add(Warning.fromString("Illegal material specification, ignoring."));
 			return;
 		}

core/src/main/java/info/openrocket/core/file/openrocket/importt/MotorConfigurationHandler.java

@@ -1,6 +1,7 @@
 package info.openrocket.core.file.openrocket.importt;
 
 import java.util.HashMap;
+import java.util.Map;
 
 import org.xml.sax.SAXException;
 
@@ -69,8 +70,8 @@ class MotorConfigurationHandler extends AbstractElementHandler {
 			rocket.getFlightConfiguration(fcid).setName(name);
 		}
 
-		for (int stageNr : stageActiveness.keySet()) {
+		for (Map.Entry<Integer, Boolean> entry : stageActiveness.entrySet()) {
-			rocket.getFlightConfiguration(fcid).preloadStageActiveness(stageNr, stageActiveness.get(stageNr));
+			rocket.getFlightConfiguration(fcid).preloadStageActiveness(entry.getKey(), entry.getValue());
 		}
 
 		if ("true".equals(attributes.remove("default"))) {

core/src/main/java/info/openrocket/core/file/openrocket/importt/OpenRocketHandler.java

@@ -72,7 +72,7 @@ public class OpenRocketHandler extends AbstractElementHandler {
 			String str = "Unsupported document version";
 			if (docVersion != null)
 				str += " " + docVersion;
-			if (creator != null && !creator.trim().equals(""))
+			if (creator != null && !creator.trim().isEmpty())
 				str += " (written using '" + creator.trim() + "')";
 			str += ", attempting to read file anyway.";
 			warnings.add(str);

core/src/main/java/info/openrocket/core/file/rasaero/importt/RecoveryHandler.java

@@ -75,10 +75,10 @@ public class RecoveryHandler extends AbstractElementHandler {
 
         // Set the values of the recovery parameters
         for (int i = 1; i <= NR_OF_RECOVERY_DEVICES; i++) {
-            for (String e : mapParametersToVars.keySet()) {
+            for (Map.Entry<String, Object[]> entry : mapParametersToVars.entrySet()) {
-                String key = e + i;
+                String key = entry.getKey() + i;
                 if (key.equals(element)) {
-                    Object[] vars = mapParametersToVars.get(e);
+                    Object[] vars = entry.getValue();
                     if (vars.length != NR_OF_RECOVERY_DEVICES) {
                         throw new IllegalArgumentException("Recovery var array length is not 2");
                     }

core/src/main/java/info/openrocket/core/file/simplesax/AbstractElementHandler.java

@@ -31,7 +31,7 @@ public abstract class AbstractElementHandler implements ElementHandler {
 	public void closeElement(String element, HashMap<String, String> attributes,
 			String content, WarningSet warnings) throws SAXException {
 
-		if (!content.trim().equals("")) {
+		if (!content.trim().isEmpty()) {
 			warnings.add(Warning.fromString("Unknown text in element '" + element
 					+ "', ignoring."));
 		}

core/src/main/java/info/openrocket/core/motor/MotorConfigurationSet.java

@@ -5,6 +5,8 @@ import info.openrocket.core.rocketcomponent.FlightConfigurableParameterSet;
 import info.openrocket.core.rocketcomponent.FlightConfigurationId;
 import info.openrocket.core.rocketcomponent.MotorMount;
 
+import java.util.Map;
+
 /**
  * FlightConfigurationSet for motors.
  * This is used for motors, where the default value is always no motor.
@@ -49,8 +51,9 @@ public class MotorConfigurationSet extends FlightConfigurableParameterSet<MotorC
 		buffer.append(String.format(" ====== Dumping MotorConfigurationSet: %d motors in %s ======\n",
 				this.size(), mnt.getDebugName()));
 
-		for (FlightConfigurationId loopFCID : this.map.keySet()) {
+		for (Map.Entry<FlightConfigurationId, MotorConfiguration> entry : this.map.entrySet()) {
-			MotorConfiguration curConfig = this.map.get(loopFCID);
+			FlightConfigurationId loopFCID = entry.getKey();
+			MotorConfiguration curConfig = entry.getValue();
 			if (this.isDefault(loopFCID)) {
 				buffer.append("  [DEF]");
 			} else {

core/src/main/java/info/openrocket/core/motor/ThrustCurveMotor.java

@@ -246,14 +246,14 @@ public class ThrustCurveMotor implements Motor, Comparable<ThrustCurveMotor>, Se
 			// If I don't have a motor designation (will be the case if I read the
 			// thrustcurve from a file)
 			// use the motor code
-			if (motor.designation.equals("")) {
+			if (motor.designation.isEmpty()) {
 				motor.designation = motor.code;
 			}
 
 			// If I don't have a motor common name (will be the case if I read the
 			// thrustcurve from a flle)
 			// apply the motor code simplification heuristics to generate a common name
-			if (motor.commonName.equals("")) {
+			if (motor.commonName.isEmpty()) {
 				motor.commonName = simplifyDesignation(motor.designation);
 			}
 

core/src/main/java/info/openrocket/core/optimization/general/OptimizationControllerDelegator.java

@@ -1,6 +1,7 @@
 package info.openrocket.core.optimization.general;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
@@ -21,9 +22,7 @@ public class OptimizationControllerDelegator implements OptimizationController {
 	 * @param controllers the controllers to use.
 	 */
 	public OptimizationControllerDelegator(OptimizationController... controllers) {
-		for (OptimizationController c : controllers) {
+		this.controllers.addAll(Arrays.asList(controllers));
-			this.controllers.add(c);
-		}
 	}
 
 	/**

core/src/main/java/info/openrocket/core/preset/loader/DoubleUnitColumnParser.java

@@ -29,7 +29,7 @@ public class DoubleUnitColumnParser extends BaseUnitColumnParser {
 
 				Unit unit = rocksimUnits.get(unitName);
 				if (unit == null) {
-					if (unitName == null || "".equals(unitName) || "?".equals(unitName)) {
+					if (unitName == null || unitName.isEmpty() || "?".equals(unitName)) {
 						// Hmm no data... Lets assume SI
 						if (propKey.getUnitGroup() == UnitGroup.UNITS_LENGTH) {
 							unit = UnitGroup.UNITS_LENGTH.getUnit("in");

core/src/main/java/info/openrocket/core/preset/loader/ShapeColumnParser.java

@@ -49,7 +49,7 @@ public class ShapeColumnParser extends BaseColumnParser {
 		if ("0".equals(lc)) {
 			shape = Shape.CONICAL;
 		}
-		if ("".equals(lc)) {
+		if (lc.isEmpty()) {
 			shape = Shape.CONICAL;
 		}
 		if ("3".equals(lc)) {

core/src/main/java/info/openrocket/core/rocketcomponent/FlightConfigurableParameterSet.java

@@ -3,6 +3,7 @@ package info.openrocket.core.rocketcomponent;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Map.Entry;
 
 import info.openrocket.core.util.ArrayList;
@@ -38,9 +39,9 @@ public class FlightConfigurableParameterSet<E extends FlightConfigurableParamete
 	 * @param configSet the FlightConfigurableParameterSet to copy
 	 */
 	public FlightConfigurableParameterSet(FlightConfigurableParameterSet<E> configSet) {
-		for (FlightConfigurationId key : configSet.map.keySet()) {
+		for (Entry<FlightConfigurationId, E> entry : configSet.map.entrySet()) {
-			E cloneConfig = configSet.map.get(key).clone();
+			E cloneConfig = entry.getValue().clone();
-			this.map.put(key, cloneConfig);
+			this.map.put(entry.getKey(), cloneConfig);
 		}
 	}
 

core/src/main/java/info/openrocket/core/rocketcomponent/FlightConfiguration.java

@@ -313,8 +313,8 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 		if (preloadStageActiveness == null) {
 			return;
 		}
-		for (int stageNumber : preloadStageActiveness.keySet()) {
+		for (Map.Entry<Integer, Boolean> entry : preloadStageActiveness.entrySet()) {
-			_setStageActive(stageNumber, preloadStageActiveness.get(stageNumber), false);
+			_setStageActive(entry.getKey(), entry.getValue(), false);
 		}
 		preloadStageActiveness.clear();
 		preloadStageActiveness = null;

core/src/main/java/info/openrocket/core/rocketcomponent/FlightConfigurationId.java

@@ -36,7 +36,7 @@ public final class FlightConfigurationId implements Comparable<FlightConfigurati
 	 */
 	public FlightConfigurationId(final String _str) {
 		UUID candidate;
-		if (_str == null || "".equals(_str)) {
+		if (_str == null || _str.isEmpty()) {
 			candidate = UUID.randomUUID();
 		} else {
 			try {

core/src/main/java/info/openrocket/core/simulation/FlightDataBranch.java

@@ -114,9 +114,9 @@ public class FlightDataBranch implements Monitorable {
 	public void addPoint() {
 		mutable.check();
 		
-		for (FlightDataType type : values.keySet()) {
+		for (Map.Entry<FlightDataType, ArrayList<Double>> entry : values.entrySet()) {
-			sanityCheckValues(type, Double.NaN);
+			sanityCheckValues(entry.getKey(), Double.NaN);
-			values.get(type).add(Double.NaN);
+			entry.getValue().add(Double.NaN);
 		}
 		modID = new ModID();
 	}
@@ -249,8 +249,8 @@ public class FlightDataBranch implements Monitorable {
 	 * Return the number of data points in this branch.
 	 */
 	public int getLength() {
-		for (FlightDataType t : values.keySet()) {
+		for (ArrayList<Double> doubles : values.values()) {
-			return values.get(t).size();
+			return doubles.size();
 		}
 		return 0;
 	}
@@ -449,8 +449,8 @@ public class FlightDataBranch implements Monitorable {
 	public FlightDataBranch clone() {
 		FlightDataType[] types = getTypes();
 		FlightDataBranch clone = new FlightDataBranch(name, types);
-		for (FlightDataType type : values.keySet()) {
+		for (Map.Entry<FlightDataType, ArrayList<Double>> entry : values.entrySet()) {
-			clone.values.put(type, values.get(type).clone());
+			clone.values.put(entry.getKey(), entry.getValue().clone());
 		}
 		clone.minValues.putAll(minValues);
 		clone.maxValues.putAll(maxValues);

core/src/main/java/info/openrocket/core/thrustcurve/SearchRequest.java

@@ -23,7 +23,7 @@ public class SearchRequest {
 		this.manufacturer = null;
 		if (manufacturer != null) {
 			manufacturer = manufacturer.trim();
-			if (!"".equals(manufacturer)) {
+			if (!manufacturer.isEmpty()) {
 				this.manufacturer = manufacturer;
 			}
 		}
@@ -43,7 +43,7 @@ public class SearchRequest {
 			return;
 		}
 		this.common_name = common_name.trim();
-		if ("".equals(this.common_name)) {
+		if (this.common_name.isEmpty()) {
 			this.common_name = null;
 		}
 	}
@@ -52,7 +52,7 @@ public class SearchRequest {
 		this.impulse_class = null;
 		if (impulse_class != null) {
 			this.impulse_class = impulse_class.trim();
-			if ("".equals(impulse_class)) {
+			if (impulse_class.isEmpty()) {
 				this.impulse_class = null;
 			}
 		}

core/src/main/java/info/openrocket/core/unit/UnitGroup.java

@@ -758,7 +758,7 @@ public class UnitGroup {
 		double value = StringUtils.convertToDouble(matcher.group(1));
 		String unit = matcher.group(2).trim();
 
-		if (unit.equals("")) {
+		if (unit.isEmpty()) {
 			value = this.getDefaultUnit().fromUnit(value);
 		} else {
 			int i;

core/src/main/java/info/openrocket/core/util/QuaternionMultiply.java

@@ -50,7 +50,7 @@ public class QuaternionMultiply {
 		for (int i = 0; i < arg.length; i++) {
 			Value value = new Value();
 
-			if (arg[i].equals("")) {
+			if (arg[i].isEmpty()) {
 				value.sign = 0;
 			} else {
 				if (arg[i].startsWith("-")) {

core/src/main/java/info/openrocket/core/util/StringUtils.java

@@ -47,7 +47,7 @@ public class StringUtils {
 		if (s == null) {
 			return true;
 		}
-		return "".equals(s.trim());
+		return s.trim().isEmpty();
 	}
 
 	/**

core/src/main/java/info/openrocket/core/util/Transformation.java

@@ -88,8 +88,7 @@ public class Transformation implements java.io.Serializable {
 	 */
 	public Transformation(double[][] rotation, Coordinate translation) {
 		for (int i = 0; i < 3; i++)
-			for (int j = 0; j < 3; j++)
+			System.arraycopy(rotation[i], 0, this.rotation[i], 0, 3);
-				this.rotation[i][j] = rotation[i][j];
 		this.translate = translation;
 	}
 
@@ -101,8 +100,7 @@ public class Transformation implements java.io.Serializable {
 	 */
 	public Transformation(double[][] rotation) {
 		for (int i = 0; i < 3; i++)
-			for (int j = 0; j < 3; j++)
+			System.arraycopy(rotation[i], 0, this.rotation[i], 0, 3);
-				this.rotation[i][j] = rotation[i][j];
 		this.translate = Coordinate.NUL;
 	}
 

core/src/test/java/info/openrocket/core/rocketcomponent/FreeformFinSetTest.java

@@ -1222,7 +1222,7 @@ public class FreeformFinSetTest extends BaseTestCase {
 
 			final Coordinate[] actualPoints = fin.getFinPoints();
 
-			final String rawPointDescr = "\n" + fin.toDebugDetail().toString() + "\n>> axial offset: " + x_delta;
+			final String rawPointDescr = "\n" + fin.toDebugDetail() + "\n>> axial offset: " + x_delta;
 
 			Coordinate[] displayPoints = FinSet.translatePoints(actualPoints, x_delta, 0);
 			for (int index = 0; index < displayPoints.length; ++index) {

swing/src/main/java/info/openrocket/swing/communication/AssetHandler.java

@@ -57,9 +57,9 @@ public class AssetHandler {
         if (urls == null) return null;
 
         for (String url : urls) {
-            for (String ext : mapExtensionToPlatform.keySet()) {
+            for (Map.Entry<String, UpdatePlatform[]> entry : mapExtensionToPlatform.entrySet()) {
-                if (url.endsWith(ext)) {
+                if (url.endsWith(entry.getKey())) {
-                    output.put(mapExtensionToPlatform.get(ext)[0], url);    // First Platform element is enough
+                    output.put(entry.getValue()[0], url);    // First Platform element is enough
                 }
             }
         }
@@ -73,10 +73,10 @@ public class AssetHandler {
      * @return URL to download the installer for the given platform
      */
     public static String getInstallerURLForPlatform(UpdatePlatform platform, String version) {
-        for (UpdatePlatform[] platforms : mapPlatformToURL.keySet()) {
+        for (Map.Entry<UpdatePlatform[], String> entry : mapPlatformToURL.entrySet()) {
-            for (UpdatePlatform p : platforms) {
+            for (UpdatePlatform p : entry.getKey()) {
                 if (p == platform) {
-                    return String.format(mapPlatformToURL.get(platforms), version);
+                    return String.format(entry.getValue(), version);
                 }
             }
         }

swing/src/main/java/info/openrocket/swing/file/motor/MotorLoaderHelper.java

@@ -99,9 +99,7 @@ public final class MotorLoaderHelper {
 			log.debug("Loading motors from file " + input.getU());
 			try {
 				List<ThrustCurveMotor.Builder> motors = load(input.getV(), input.getU().getName());
-				for (ThrustCurveMotor.Builder m : motors) {
+				list.addAll(motors);
-					list.add(m);
-				}
 			} finally {
 				try {
 					input.getV().close();

swing/src/main/java/info/openrocket/swing/file/photo/PhotoStudioGetter.java

@@ -36,8 +36,8 @@ public class PhotoStudioGetter {
 
     public PhotoSettings getPhotoSettings() {
         if (parameters != null) {
-            for (String element : parameters.keySet()) {
+            for (Map.Entry<String, String> entry : parameters.entrySet()) {
-                processElement(element, parameters.get(element));
+                processElement(entry.getKey(), entry.getValue());
             }
         }
         return p;
@@ -166,7 +166,7 @@ public class PhotoStudioGetter {
         }
 
         if ("sky".equals(element)) {
-            if (content.equals("")) {     // Case where sky is null
+            if (content.isEmpty()) {     // Case where sky is null
                 p.setSky(null);
                 return;
             }

swing/src/main/java/info/openrocket/swing/gui/adaptors/EnumModel.java

@@ -1,6 +1,7 @@
 package info.openrocket.swing.gui.adaptors;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.EventObject;
 
 import javax.swing.AbstractListModel;
@@ -66,9 +67,7 @@ public class EnumModel<T extends Enum<T>> extends AbstractListModel<T>
 		else 
 			this.values = (T[]) enumClass.getEnumConstants();
 
-		for (T e : this.values){
+		this.displayedValues.addAll(Arrays.asList(this.values));
-			this.displayedValues.add( e );
-		}
 		this.nullText = nullText;
 		
 		stateChanged(null);  // Update current value

swing/src/main/java/info/openrocket/swing/gui/configdialog/FreeformFinSetConfig.java

@@ -366,7 +366,7 @@ public class FreeformFinSetConfig extends FinSetConfig {
 				bufferHeader.append(table.getColumnName(j));
 				bufferHeader.append(", ");
 			}
-			writer.write(bufferHeader.toString() + "\r\n");
+			writer.write(bufferHeader + "\r\n");
 
 			//write row information
 			for (int i = 0; i < nRow; i++) {
@@ -375,7 +375,7 @@ public class FreeformFinSetConfig extends FinSetConfig {
 					buffer.append(table.getValueAt(i, j));
 					buffer.append(", ");
 				}
-				writer.write(buffer.toString() + "\r\n");
+				writer.write(buffer + "\r\n");
 			}
 			writer.close();
 

swing/src/main/java/info/openrocket/swing/gui/dialogs/optimization/GeneralOptimizationDialog.java

@@ -1025,8 +1025,7 @@ public class GeneralOptimizationDialog extends JDialog {
 			list.add(m);
 		}
 		
-		for (Object key : simulationModifiers.keySet()) {
+		for (List<SimulationModifier> list : simulationModifiers.values()) {
-			List<SimulationModifier> list = simulationModifiers.get(key);
 			list.sort((o1, o2) -> o1.getName().compareTo(o2.getName()));
 		}
 		

swing/src/main/java/info/openrocket/swing/gui/dialogs/optimization/OptimizationPlotDialog.java

@@ -144,8 +144,8 @@ public class OptimizationPlotDialog extends JDialog {
 		// Create the optimization path (with autosort)
 		XYSeries series = new XYSeries(trans.get("plot1d.series"), true, true);
 		List<String> tooltips = new ArrayList<String>();
-		for (Point p : evaluations.keySet()) {
+		for (Map.Entry<Point, FunctionEvaluationData> entry : evaluations.entrySet()) {
-			FunctionEvaluationData data = evaluations.get(p);
+			FunctionEvaluationData data = entry.getValue();
 			if (data != null) {
 				if (data.getParameterValue() != null) {
 					Value[] state = data.getState();
@@ -153,7 +153,7 @@ public class OptimizationPlotDialog extends JDialog {
 					tooltips.add(getTooltip(data, parameter));
 				}
 			} else {
-				log.error("Could not find evaluation data for point " + p);
+				log.error("Could not find evaluation data for point " + entry.getKey());
 			}
 		}
 		

swing/src/main/java/info/openrocket/swing/gui/figure3d/RealisticRenderer.java

@@ -127,9 +127,7 @@ public class RealisticRenderer extends RocketRenderer {
 		gl.glLightModeli(GL2.GL_LIGHT_MODEL_COLOR_CONTROL, GL2.GL_SEPARATE_SPECULAR_COLOR);
 		
 		float[] convertedColor = this.convertColor(a, alpha);
-		for (int i=0; i < convertedColor.length; i++) {
+		System.arraycopy(convertedColor, 0, color, 0, convertedColor.length);
-			color[i] = convertedColor[i];
-		}
 		
 		gl.glMaterialfv(GL.GL_FRONT, GLLightingFunc.GL_DIFFUSE, color, 0);
 		gl.glMaterialfv(GL.GL_FRONT, GLLightingFunc.GL_AMBIENT, color, 0);

swing/src/main/java/info/openrocket/swing/gui/figure3d/RocketFigure3d.java

@@ -13,6 +13,7 @@ import java.awt.event.MouseEvent;
 import java.awt.geom.AffineTransform;
 import java.awt.image.BufferedImage;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -600,8 +601,7 @@ public class RocketFigure3d extends JPanel implements GLEventListener {
 	public void setSelection(final RocketComponent[] selection) {
 		this.selection.clear();
 		if (selection != null) {
-			for (RocketComponent c : selection)
+			this.selection.addAll(Arrays.asList(selection));
-				this.selection.add(c);
 		}
 		internalRepaint();
 	}

swing/src/main/java/info/openrocket/swing/gui/main/componenttree/ComponentTreeTransferHandler.java

@@ -89,7 +89,7 @@ public class ComponentTreeTransferHandler extends TransferHandler {
 			}
 		}
 
-		log.info("Creating transferable from component " + sb.toString());
+		log.info("Creating transferable from component " + sb);
 		return new RocketComponentTransferable(components);
 	}
 	

swing/src/main/java/info/openrocket/swing/gui/plot/SimulationPlot.java

@@ -21,6 +21,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -453,7 +454,7 @@ public class SimulationPlot {
 
 	private void fillEventLists(int branch, List<Double> eventTimes, List<String> eventLabels,
 								List<Color> eventColors, List<Image> eventImages) {
-		HashSet<FlightEvent.Type> typeSet = new HashSet<>();
+		Set<FlightEvent.Type> typeSet = new HashSet<>();
 		double prevTime = -100;
 		String text = null;
 		Color color = null;

swing/src/main/java/info/openrocket/swing/gui/preset/PresetEditorDialog.java

@@ -2192,10 +2192,10 @@ public class PresetEditorDialog extends JDialog implements ItemListener {
 				JOptionPane.showMessageDialog(null, "A material must be selected.", "Error", JOptionPane.ERROR_MESSAGE);
 				return null;
 			}
-			if (!pcLineCount.getText().equals("")) {
+			if (!pcLineCount.getText().isEmpty()) {
 				props.put(ComponentPreset.LINE_COUNT, Integer.parseInt(pcLineCount.getText()));
 			}
-			if (!pcSides.getText().equals("")) {
+			if (!pcSides.getText().isEmpty()) {
 				props.put(ComponentPreset.SIDES, Integer.parseInt(pcSides.getText()));
 			}
 			props.put(ComponentPreset.LINE_LENGTH, pcLineLength.getValue());

swing/src/main/java/info/openrocket/swing/gui/print/DesignReport.java

@@ -668,7 +668,7 @@ public class DesignReport {
 	protected void runSimulations(List<Simulation> simulations) {
 		if (window != null) {
 			log.debug("Updating " + simulations.size() + "simulations using SimulationRunDialog");
-			Simulation[] runMe = simulations.toArray(new Simulation[simulations.size()]);
+			Simulation[] runMe = simulations.toArray(new Simulation[0]);
 			new SimulationRunDialog(window, rocketDocument, runMe).setVisible(true);
 		} else {
 			/* This code is left for compatibility with any developers who are

swing/src/main/java/info/openrocket/swing/gui/print/FinMarkingGuide.java

@@ -255,10 +255,10 @@ public class FinMarkingGuide extends JPanel {
 
 		int column = 0;
 		
-		for (BodyTube next : markingGuideItems.keySet()) {
+		for (Map.Entry<BodyTube, List<ExternalComponent>> entry : markingGuideItems.entrySet()) {
-			double circumferenceInPoints = PrintUnit.METERS.toPoints((next.getOuterRadius() + PAPER_THICKNESS_IN_METERS) *
+			double circumferenceInPoints = PrintUnit.METERS.toPoints((entry.getKey().getOuterRadius() + PAPER_THICKNESS_IN_METERS) *
 					TWO_PI);
-			List<ExternalComponent> componentList = markingGuideItems.get(next);
+			List<ExternalComponent> componentList = entry.getValue();
 			//Don't draw the lug if there are no fins.
 			if (hasFins(componentList)) {
 				length = (int) Math.ceil(circumferenceInPoints);

swing/src/main/java/info/openrocket/swing/gui/print/components/CheckTreeSelectionModel.java

@@ -134,7 +134,7 @@ public class CheckTreeSelectionModel extends DefaultTreeSelectionModel {
                     toBeRemoved.add(selectionPath);
                 }
             }
-            super.removeSelectionPaths(toBeRemoved.toArray(new TreePath[toBeRemoved.size()]));
+            super.removeSelectionPaths(toBeRemoved.toArray(new TreePath[0]));
         }
 
         // if all siblings are selected then deselect them and select parent recursively 

swing/src/main/java/info/openrocket/swing/gui/print/components/RocketPrintTree.java

@@ -185,7 +185,7 @@ public class RocketPrintTree extends JTree {
 											INITIAL_CHECKBOX_SELECTED));
 			}
 		}
-		return nodes.toArray(new CheckBoxNode[nodes.size()]);
+		return nodes.toArray(new CheckBoxNode[0]);
 	}
 	
 	/**

swing/src/main/java/info/openrocket/swing/gui/simulation/SimulationConfigDialog.java

@@ -254,7 +254,7 @@ public class SimulationConfigDialog extends JDialog {
 
 			private void setText() {
 				String name = field.getText();
-				if (name == null || name.equals(""))
+				if (name == null || name.isEmpty())
 					return;
 				simulationList[0].setName(name);
 

swing/src/main/java/info/openrocket/swing/gui/util/SwingPreferences.java

@@ -16,6 +16,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Set;
 import java.util.prefs.BackingStoreException;
 import java.util.prefs.Preferences;
@@ -677,12 +678,12 @@ public class SwingPreferences extends info.openrocket.core.startup.Preferences i
 	public void storeDefaultUnits() {
 		Preferences prefs = PREFNODE.node("units");
 		
-		for (String key : UnitGroup.UNITS.keySet()) {
+		for (Map.Entry<String, UnitGroup> entry : UnitGroup.UNITS.entrySet()) {
-			UnitGroup group = UnitGroup.UNITS.get(key);
+			UnitGroup group = entry.getValue();
 			if (group == null || group.getUnitCount() < 2)
 				continue;
 			
-			prefs.put(key, group.getDefaultUnit().getUnit());
+			prefs.put(entry.getKey(), group.getDefaultUnit().getUnit());
 		}
 	}
 	

swing/src/main/java/info/openrocket/swing/gui/widgets/MultiSlider.java

@@ -228,9 +228,7 @@ public class MultiSlider extends JSlider {
 			values[0] = getMinimum();
 			values[num_of_values - 1] = getMaximum();
 			int[] def = createDefaultValues(getMinimum(), getMaximum(), num_of_values - 2, false);
-			for (int i = 0; i < def.length; i++) {
+			System.arraycopy(def, 0, values, 1, def.length);
-				values[i + 1] = def[i];
-			}
 		}
 		return values;
 	}

swing/src/main/java/info/openrocket/swing/gui/widgets/SearchableAndCategorizableComboBox.java

@@ -151,8 +151,8 @@ public class SearchableAndCategorizableComboBox<E, T> extends JComboBox<T> {
 
 	private T[] extractItemsFromMap(Map<E, T[]> itemGroupMap) {
 		Set<T> uniqueItems = new HashSet<>(); // Use a Set to ensure uniqueness
-		for (E group : itemGroupMap.keySet()) {
+		for (T[] ts : itemGroupMap.values()) {
-			uniqueItems.addAll(Arrays.asList(itemGroupMap.get(group)));
+			uniqueItems.addAll(Arrays.asList(ts));
 		}
 		ArrayList<T> items = new ArrayList<>(uniqueItems);
 		return items.toArray((T[]) new Object[0]);
@@ -166,9 +166,9 @@ public class SearchableAndCategorizableComboBox<E, T> extends JComboBox<T> {
 		menu.addSeparator(); // Separator between search field and menu items
 
 		// Fill the menu with the groups
-		for (E group : itemGroupMap.keySet()) {
+		for (Map.Entry<E, T[]> entry : itemGroupMap.entrySet()) {
-			JMenu groupList = new JMenu(group.toString());
+			JMenu groupList = new JMenu(entry.getKey().toString());
-			T[] itemsForGroup = itemGroupMap.get(group);
+			T[] itemsForGroup = entry.getValue();
 
 			if (itemsForGroup != null) {
 				for (T item : itemsForGroup) {